The present invention relates to a magnet assembly. In particular, the present invention relates to a magnet assembly for a voice coil motor for a data storage device.
A disc drive includes a plurality of stacked discs which are rotationally supported relative to a disc spindle and an actuator assembly movably supporting a plurality of data heads for reading and writing data to the discs. The actuator assembly includes an actuator drive typically a voice coil motor for actuating or positioning the heads relative to selected data tracks of the discs. The voice coil motor includes a magnet assembly defining a permanent magnetic field and an energizable coil coupled to an actuator block supporting the heads. A voltage is supplied to the coil to selectively operate and move the actuator block to align the data heads relative to predetermined data tracks of the disc.
A typical magnet assembly includes upper and lower pole plates or backirons which are supported in opposed spaced relation and at least one magnet coupled to one of the backirons to define a flux gap therebetween. An energized coil moves in the flux gap between the upper and lower pole plates and the magnet. For proper operation of the voice coil motor, magnets must be accurately aligned and assembled to upper and lower pole plates; and upper and lower pole plates should be accurately aligned and connected for accurate head placement relative to selected data tracks. The magnetic flux or force of the magnetic components makes it difficult to handle and assemble magnets relative to upper and lower pole plates. The attraction force between magnetic components must be controlled for placement and assembly of magnets and pole plates. The present invention addresses these and other problems, and offers advantages over the prior art.
The present invention relates to a magnet assembly including spacers having chamfered posts insertable into post holes of opposed spaced backirons. The chamfered posts are self centering in the post holes of the backirons to assemble the magnet assembly. Pole plates or backirons can be assembled to spacers with the chamfered posts using the magnetic attractive force of the magnets supported by the upper or lower pole plates. Chamfered posts at a first end of spacers are inserted into post holes on a first backiron. A second backiron is supported spaced from the first backiron by an assembly slide to retain the second backiron against the magnetic attraction prior to assembly. The assembly slide is withdrawn so that the second backiron is attracted toward the first backiron and chamfered spacer posts are inserted into post holes on the second backiron for assembly.